This application requests five years of support for a collaborative, multidisciplinary program of research on social neuroscience in autism and related disorders. This application, submitted as a STAART autism center, builds on important resources and research programs. It is concerned with increasing the understanding of the processes underlying the social-communicative and social-affective functioning of individuals with autism and related conditions. The focus of the grant is on integrating advances in neuroscience and genetics in understanding specific neurodevelopmental processes and risk factors and using this understanding in treatment studies. Objectives include characterization of visual scanning patterns of social stimuli, development of simple behavioral screening methods for young children at risk for autism, to determine whether young children with symptoms of autism display distinctive listening preferences as compared to developmentally delayed children, to assess the potential utility of computer assisted face training in autism with a goal of improving face perception skills and enhancing fusiform face area activity as seen on fMRI facial expression and normalization of visual scanning. In addition we propose to characterize the nature of anxiety disorders, particularly social anxiety disorder, in children and adolescents with PDD and to evaluate the effects of the selective serotonin reuptake inhibitor, fluvoxamine, in a randomized double-blind, placebo-controlled trial. Finally we plan to conduct a series of interrelated genetic studies with the overarching aim of identifying genetic mechanisms of social disability. Six projects and two core resources are proposed. Projects include: (I) Eye tracking studies of social engagement in infants and toddlers with autism, (II) Behavioral indices of joint attention in autism in young children, (III) Precursors to social communication in autism and related disorder, (IV) Molecular and family genetic studies of social phenotypes in autism, (V) Behavioral and neural plasticity in face recognition, and (VI) Fluvoxamine in the treatment of children and adolescents with social anxiety disorder.